2020 update : JC Verdier La Platine

Albert,

The spindle head of the stock Philips, low torque, motor....

The Verdier uses a powerful, High torque, low inertia, core-less DC regulated motor.

And I feel it is the electrics of the motor assembly that is at fault for speed instability.

I somehow think that a motor with a servo system works best.

Here's a logical explanation from Charles Michlin (Azzolina Audio): "In the era when the Verdier controller was developed the LM317 voltage regulator was probably an advanced device. However today there is a greater understanding of motor control. A motor acts as a generator in operation and this back EMI causes error in controllers like the LM317. As a result they fall in and out of regulation erratically. There are newer chips designed for motor control which are immune to this problem. There are also circuits of greater sophistication which can self correct speed variations without the complications and problems of closed loop feedback."

@lbelchev Thank you for pointing out my mistake. I believe it is not the only one I have made. See below.

@audioquest4life I had thought I understood the braking action. Because of your question, I took a look again at the comment on a past thread by @ct0517 :

"If you actually cut the thread with scissors I am willing to bet it stops in much less than 7.5 revolutions as it is the same friction principle as the magnetically levitated Platine but using oil instead"

The comment described first turning off the motor and observing the number of rotations before the platter comes to a complete stop. It requires 7.5 rotations / revolutions. This is consistent with what I observed on my TT, anywhere from 7.25- 7.75 revolutions. 

However, when I remove the thread with the motor running ( i didn't actually cut the thread ), I observe about 20 + revolutions before the platter comes to a complete stop. The comment above seems to indicate that the platter should stop with maybe 3-4 revolutions and that would supposedly show the 'braking action'. My TT did not behave as such. The 20 + revolutions on my TT is more likely the platter coming to a stop due to a natural loss of rotational inertia, rather any 'braking' action of the spindle and shaft.

So in short, I am realising that my TT did not exhibit the supposed braking that was observed by others. But then again, having such a heavy platter come to a complete stop within 3-4 revolutions while in free rotation would indicate some heavy forces acting on it. That force is not present on my TT. I must have made a mistake in proclaiming that I have understood the braking of the platter on a La Platine. I may again need to be enlightened.

@vuckovic  Some of your tweaks and preferences are quite different from mine. But as my last post indicated, this is a TT that seems to invite differences of operational preferences. 

Using the stock motor with a custom Delrin pulley to accomodate a tape drive is novel to me. I had thought that thread drive with a more accurate motion was the way to go. 

The most interesting is your spindle ball comments. The interaction of the ball with the platter would take some force off the magnetic repulsion,  increasing bass performance and overall dynamics. This is consistent with a review I read regarding the Callas Audio Mod Kit. The Mod Kit was used to reduce the magnetic levitation forces in order to improve bass performance. The reviewer also made reference to the The Caliburn table with similar principles. 

Finally, as one who owns both the Airforce 3 and the La Platine, I wondered if you might share some thoughts of the two table. I started this post because a local audio dealer mentioned that nowadays given a choice between a La Platine and a TechDas, his clients mostly prefers the latter. He thought that was a pity as the La Platine was as worthy a TT. I would appreciate some insights.

ledoux1238
Somehow the combination of concrete, raisin, and stone chips doesn't seem to be a good resonance damper. I would like to be enlightened.

You are forgetting about the the Air Albert.

The resonance of the plinth with its suspension is about 5Hz and it is well absorbed by the air cavities. JC Verdier

Removing the pneumatic feet defeats the design.

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re; the motor

the stock motor gearing can be heard continuing after it is shut off. It reminds of a watch one winds up and one of the reasons, I assume, speed stability remains when I shut it off and on.

Your rotation numbers I am not sure of.
Going by memory (I am not at the property) when motor is shut off the gearing can be heard continuing and the platter spins for close to thirty seconds before coming to a stop. When it is running and the thread is cut, the time  to stoppage is much.much shorter. Braking action very evident.

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fyi et al
Before I even considered La Platine I was attempting to build an ultimate turntable with the direct drive project. I went through various stages. The next version would have replaced the Technics square casing with a Denon circular one. But then I discovered thread drive with the modded - VPI TNT.
Decoupling of components is important. My ET 2.5 tonearm air bearing spindle that holds the armtube/cartridge at one and counterweights at the other, was already isolated / decoupled with a film of air 360 degrees. No mechanical contact.
The Direct Drive mdf layered plinth with pneumatic footers was decoupled from the platform it sits on with the AT616 footers.  The casing for the motor platter system I attempted to decouple using 4 stainless steel legs. Raising it high with only 4 contact points. I moved to this after I realized all platters/motors encased in plinths color the sound. Many search for the right "color" in materials . 8^0.
The Tonearm brass pillar (20 plus pounds) attached to the plinth raises the ET 2.5 and allows for a happy face loop of single shot wiring.

When I became aware of La Platine, I saw it as a natural extension and progression of my own project, plus it had the decoupled and raised platter system. I could never ever have imagined this on my own efforts. Most importantly, it was designed as a thread design from the get go, not a modified belt drive like my TNT. I was not aware of the braking system at the time.

Cheers 
Stay Safe, Social Distancing, Stay Healthy 

Sorry Ledoux1238 for late response - too busy elsewhere. It is difficult for me to give you exact difference between AF-3P and La Platine. I have many arms and cartridges and until you do not put the same combo on both TT you can not be sure about direct A-B outcome. I moved last week Glanz MH-124s and VdH Colibri MS from Verdier to AF and got some conclusions which mirror my previous experience with AF.
AF-3P is much more quieter. This brings more transparency, more details and bigger soundstage. AF is also more dynamic and more neutral. Verdier is smoother with more body and more darker - some people would say - more natural. But do not forget that this is very tweaked Verdier. Last year I got from my friend another Verdier motor with battery power supply made by Graham Tricker ( Tron ). Since I put Mylar tape on my Verdier I have never compared it with regular belt and metal pulley. I liked it from the beginning and did not care - you can read impression about it in my previous post. But when I got Graham motor I tried rubber, original thread and some special fishing string as a belt again before I changed it to Delrin pulley and mylar tape. Difference was huge and striking. The highs were so dirty and compressed! I could not believe it. I measured speed (3150hz) and W&F ( 0.07% ) using AnalogMagik software. The only conclusion would be that these tiny thread and string transmitted huge noise to platter! Hard to believe but it is my experience. Another advice for Verdier fans would be to use use the shortest length of belt possible which should not be tight in tension. Platter should be mostly turn from its own weight inertia.
AF-3P is engineering marvel. Simple, beautiful, easy to operate - real jewel! From my experience it is the best sounding TechDAS model regardless the price. Better than any old Micro as well. The only TT I would go after AF-3P would be Karmeli’s American Sound AS-2000. I think Dave helped TechDAS in developing 3P. Very similar designs but AS-2000 is a piece of art!
In conclusion - AF is better but much more expensive than Verdier. If money is not object I would go with AF. In case you have to save money to afford it - forget AF. Keep Verdier and enjoy your life. I would rather take La Platine than ANY TW Akustic or Brinkmann....